Estimates of the majority photocarrier mobility-lifetime ( mu tau ) product obtained from time-of-flight transient photoconductivity and from steady-state photoconductivity are compared. It is shown that in principle both experiments measure the integral of the transient drift mobility. Estimates of mu tau for undoped amorphous hydrogenated silicon (a-Si:H) based on the two techniques disagree by a factor of approximately 100 in comparable specimens. Possible origins of the discrepancy are discussed in relation to experimental procedures, optical bias effects and surface inhomogeneity. It is concluded that in undoped a-Si:H the dangling-bond defect observed in electron-spin resonance acts predominantly as a photocarrier trap and not as a simple recombination center.
|Original language||English (US)|
|Number of pages||6|
|Journal||Philosophical Magazine Letters|
|State||Published - Feb 1987|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics